Sulfur containing steroid compositions



United States PatentO SULFUR CONTAINING STEROID COMPOSITIONS Barry M.Bloom and Gerald D. Laubach, Jackson Heights,

N. Y., assignors to Chas. Pfizer & Co., Inc., Brooklyn,

N. Y., a corporation of Delaware No Drawing. Application February 29,1956 Serial No. 568,451 7 Claims. (Cl. 167-52) This invention isconcerned with certain novel sulfur containing stereoid compounds whichare hormonally inactive and are central nervous system depressants.These materials are pregnane derivatives which contain a sulfur atomattached at either the 3 or the 21 position of the nucleus. Thesematerials also contain ionic ester groups at the 3 and/ or the 21positions and are especially useful as anesthetic agents, and asintermediates in organic synthesis. 7

The valuable compounds of this invention are generically represented bythe following structural formula CH2-E The stereochemical relationshipof the hydrogen at C is not indicated since the compounds of thisinvention belong to both the normaland allo-serie's. This formula isintended to be generic to both series. Similarly the group D whenmonovalent is situated in either the a or the B configuration. Thevaluable products of this invention are related to the series of watersoluble esters of pregnanolones patented by G. D. Laubach (U. S. PatentNo. 2,708,651, granted May '17, 1955), but they contain a nuclearlyattached sulfur atom at the 3 or the 21 position.

They are related in the same way to the ionic esters disclosed andclaimed in copending application Serial No. 568,450 filed herewith.These compounds have certain advantages over their oxygen analogs inthat they have improved phlebitic and other pharmaceutical propertieswhich makes them particularly desirable for administration as centralnervous system depressants.

D and/or E may be selected from a variety of organic units and may beionic ester groups having one of the following formulas wherein L ischosen from the group consisting of an.

alkylene radical, a hydroxy-alkylene radical, the lower hydrocarbonethers thereof, the lower hydrocarbon carboxylic acid esters thereof, amercaptoalkylene radical, the lower hydrocarbon sulfides thereof, thelower hydrocarbon carboxylic acid thioesters thereof, an amino-2,878,157 Patented Mar. 17, 1959 hydrocarbon'group is an aliphatic,cycloaliphatic, aromatic or araliphatic group and a hydrocarbon acid isthe corresponding carboxylic acid. The L group may also be an hydrogenatoms or lower hydrocarbon groups having up .to about six carbon. atomsin each'group. At least one of said substitutents is a hydrogen atoms ineach case. The following illustrate some of the various formulas for Y+.

M+ is a cation selected from the group consisting of sodium, potassiumand ammonium of the types just described for Y+. Z is apharmacologically acceptable anion. This term has a definite meaning tothose skilled in the art. By this is meant an anion of an acid which canbe used in physiological preparations to neutralize a basic medicinalagent. Such materials may be toxic at certain dosage-levels but at theconcentrations required with the benzoic, toluie and phenylacetic acids.In other words a.

neutralized medicinal agent, toxic effects due to the anion are absent.Examples of such anions are chloride, bromide, sulfate, methosulfate,phosphate, tartrate, gluconate, citrate, succinate, maleate, etc.

.,Further structures from which D and E may be selected include thehydroxyl group, and lower hydrocarbon carboxylic acid esters thereofcontaining up to about eight carbon atoms in the added unit, a hydrogenatom, and a mercapto group. The mercapto group may be furthersubstituted with a lower hydrocarbon or hydrocarbon carboxylic acidgroup containing up to about eight carbon atoms to form a sulfide orthiol ester function. D alone may also be a keto group. In the foregoingdiscussion, the alkylene radical referred to is an aliphatic alkyl.group containing two unoccupied valences which are available forattachment as shown for L in the structural formulas. This group may bestraight or branched but it is so constituted that its principal chain,that is the chain between the two unoccupied valences, containsup toabout six carbon atoms. The hydroxyalkylene, mercaptoalkylene, andaminoalkylene radicals are similarly constituted, but they contain ahydroxyl group, a mercapto group or an amino group attached to thealkylene group either .at one of the carbon atoms of the principal chainor to a carbon atom, of one of the branches if the alkylene group isbranched. The hydroxyl,vmercapto or amino groups so attached may befurther substituted by a lower hydrocarbon group or a lower hydrocarboncarboxylic acidv group as already described. The following formulas willfurther illustrate thetype of structure of the alkylene,hydroxyalkylene, substituted hydroxyalkylene, mercaptoalkylene,substituted mercaptoalkylene, aminoalkylene, andxsubstituted aminoalkylene .groups.

It will be noted'that again these groups may be straight and However, itis preferred that said heterogroups be attached only to saturated carbonatoms. That is they appear within the principal chain of the L group andnot at either end. More than one carbon atom is sometimes replaced by aheterogroup of the above types, but as a practical matter the compoundscontaining only one heterogroup in the L group are more readilysynthesized and are therefore preferred.

The foregoing discussion of the structures of the D and E groups in thegeneric formula can be summarized as follows.

D is selected from the group consisting of (a) ionic ester groups of theformula:

and -S-S and wherein said heterogroups are attached to saturated carbonatoms and said L group contains up to about six atoms in its principalchain; M+ is a cation selected from the group consisting of sodium,potassium and NR+, each R represents a member of the group consisting ofa hydrogen atom, and a lower hydrocarbon group containing up to aboutsix carbon atoms; Z is a pharmacologically acceptable anion; (b)hydroxyl, and the lower hydrocarbon carboxylic acid esters thereofcontaining up to about eight carbon atoms in the added unit; (6) keto;(d) mercapto, lower hydrocarbon sulfides, and hydrocarbon carboxylicacid thioesters thereof having up to about eight carbon atoms in theadded unit.

E is selected from the group consisting of (a) ionic ester groups asdefined above; (b) hydroxyl, and lower hydrocarbon carboxylic acidesters thereof containing up to about eight carbon atoms in the addedunit; (c) hydrogen; (d) mercapto, lower hydrocarbon sulfides, and lowerhydrocarbon carboxylic acid esters thereof com taining up to about eightcarbon atoms in the added unit; and with atleast one of D and E being anionic ester group as defined above andone of'D and E containingnuclearly attached sulfur.

To further illustrate the structures of the valuable sulfur containingsteroids of this invention, a few typical formulas are given-below.

e e i n v(CzHOaNHO l CH2) CHzCS- A CHzOCOCHnCHzC OzNBPregnane-3,20rdione-2l-thiol and allo-pregnane-ZO-one- 2l-ol-3a-thiolare particularly useful intermediates in the synthesis of the valuablewater soluble sulfur containing steroid ionic esters of this invention.The latter material is also useful as an intermediate in the preparationof similar 3-desoxyionic esters in the pregnane series since the sulfurat the 3 position can be removed by treatment with Raney nickel. The3-desoxyionic esters are described in copending U. S. application SerialNo. 508,803, filed May, 1955 (now U. S. Patent 2,820,737 issued January21, 1958. These two intermediates themselves have been found to becentral nervous system depressants. The former material was readilyprepared from pregnane 3,20'di0fl6r20'01 by first preparing theptoluenesulfonic acid ester of the 21 hydroxyl group and then treatingthis with potassium iodide and potassium thioacetate according to aknown procedure for preparing thioacetate esters. The acetyl group wasthen removed by hydrolysis yielding the 2l-mercapto compound. This isillustrated by Equation 1.

CQCHzOH GE:

GQGHzOSGsGuHgCHs-D OHBSH The starting material,pregnane-3,20-dione-2l-ol was obtained by the catalytic hydrogenation ofdesoxycorticosterone. The details of this process are described incopending application, Serial No. 484,561, filed January 27, 1955, andnow abandoned.

Allo-pregnane-20-one-21-ol-3a-thiol is prepared by a similar sequence ofreactions starting with allo-pregnane- 20-one-3;9,21-diol-21-acetate.Conversion of the free hydroxyl group to the p-toluenesulfonate ester,followed by treatment with potassium thioacetate, as described above,yielded the 3u-thioacetate. This thioacetate was desulfurized bytreatment with Raney nickel providing the 3-desoxy intermediate forpreparing the 3- desoxyionic esters referred to above. Hydrolysis of thediester yielded the desired mercapto compound. This process isillustrated in Equation 2.

CHaO COCH:

C'HzOC 0 CH1 CO CH9 1J-C aCoH4S02O I l COCHzO COCHB CH:

01130 os- I ([JHzOH CO CH3 ;These two intermediates were then readilyconverted to a variety of the valuable anesthetic agents of thisinvention by the application of processes of U. S.

2,708,651, issued to G. D. Laubach, May 17, 1955, and

of copending application Serial No. 568,450 filed herewith. For example,succinoylation of the 3 and 21 mercapto or hydroxyl groups of the abovematerials yielded the hemisuccinate esters or thioesters. The

a sodium, potassium, ammonium and substituted ammonium salts of thesehemisuccinates are water soluble and possess the unique property ofdepressing the central nervous system when administered to an animal.Salts containing these particular cations are preferred since they are,in addition, well tolerated by the animal body.

Preparation of these materials is shown in Equations 3 and 4.

C O CHaSH CH3 C O CHQSC CHrCHaC 0211 CH:

CII'HzOH CO I CH:

(EH20 if CH2OH2CO2H C 0 CH3 u HOzCCHzCHaCS These succinoylations werecarried out by treatment of the pregnane derivatives in pyridine with anexcess of succinic anhydride.

Treatment of the above mercapto steroids with chloroacetyl chlorideyielded the chlorothioacetate ester which was also useful as anintermediate in the preparation of other water soluble ionic esterscontaining sulfur at the 3 or the 21 positions. This material contains areactive halogen atom that is readily replaced by reaction with amines,alcohols, amino acids, etc. Use of difunctional amines and alcoholsyielded products containing groups which were used to prepare saltswhich confer water solubility on the molecule. Useful hydrophilic groupsof this type include the acid addition salts of esters containing aminofunctions and certain metal salts and the amine salts of thosecontaining acidic functions. These materials likewise have proven to beuseful as intravenous anesthetic agents. Two examples of suchpreparations are illustrated in Equation 5.

CE: I

H C 011230 CH:N(CHJ)2.HCI CH3 course, be employed. The above steroidhalf-acid esters are also useful for the preparation of water solubleamides and carbohydrate esters which are useful as central nervoussystem depressants. Adaptations of processes described in copending U.S. application, Serial No. 549,514, filed November 28, 1955, relating tothe preparation of such compounds in the pregnane series can be readilydevised for use with the valuable sulfur containing half-acid esterintermediates of this invention.

A convenient alternative route to the preparation of the types ofcompounds illustrated by Equation involves, for example, treatment ofthe p-toluenesulfonate esters of Equations 1 and 2 withu-chloropotassium thioacetate rather than potassium thioacetate. Thisyields the same a-chloroacetyl ester which was obtained in Equation 5,and similarly the B-substituted compound. Syntheses of this type areillustrated by Equations 6 and 7.

CH: CHzOSOsCeHrGHs-p ii CHzSCCHzCl CH: l

ll CHzSC 011,01

our 4) V 3 Various modifications of the above methods may, of

O CHaOi JCHs 1? CHaOCCHI GO It is apparent that many types of synthesesmay be used to prepare the valuable compounds of this invention. Manyadditional methods will occur to those skilled in the art. Thedistinguishing structural feature of the valuable water solubleanesthetic agents of this invention, however, is that they contain anuclearly attached sulfur atom at the 3 or the 21 position of thepregnane nucleus. This sulfur atom is sometimes esterified by a watersoluble ionic ester group as described above or it is unsubstituted andthe water soluble ionic ester group appears at another position in themolecule. The sulfur atom is also sometimes substituted by other organicgroups to form, for example, sulfides or thioesters.

The valuable sulfur containing water soluble ionic ester anestheticagents of this invention were tested in mice by administering themintravenously in sterile aqueous solutions. Varying dosage levels wereused with diiferent groups of mice. From this type of an experiment itwas possible to determine at once the approximate toxicity andanestheticactivity of these compounds. For example, dosages of 15, 30, 60, 120 and240 mg./kg. were administered to different groups of mice in sterileaqueous solutions. The groups of mice receiving dosages exceeding thetoxic limit died. At the lower dosage levels anesthesia resulted. Thosethat received doses below the anesthetic level were substantiallywithout symptoms. The anesthetic activity was determined by noting thesleeping time of the mice and by the duration of the loss of rightingreflex experienced. Based on the data obtained in this manner with mice,the materials were administered first to dogs and then to monkeys atdosages calculated to give the anesthetic effect without harm to theanimals. Confirmation of the results obtained in the mouse test wasobtained although there were, of course, some species differences. insensitivity. These compounds were found to be similarly active in humanbeings.

The preferred use of the valuable central nervous system depressants ofthis invention is in anesthesia. They are particularly well suited foruse as pre or basal anesthetics in conjunction with inhalationanesthetics such as nitrous oxide, cyclopropane, and diethyl ether. Forthis type ofuse intravenous administration is preferred since the eifectof the drug generally takes place promptly when administered in thisfashion. This is necessary so that the anesthetist will have closecontrol of the degree of central nervous system depression of thepatient. The

salts of these materials, that is the acid addition, the metal and theamine salts are water soluble and therefore well suited for this purposesince water and water containing small proportions of certain organicsolvents such as glycerol or propylene glycol are about the onlysolvents that can be employed in human intravenous therapy. Thesematerials can be prepared for use as sterile solid compositions byblending them with various excipients and carriers and then sterilizingthe solid mixture for example with ethylene oxide, or they can be usedalone without solid diluents when sterilized in such a fashion. Thesterile solid is then dissolved in sterile water prior to use.Alternatively, the unsterilized solid composition or compound can bedissolved in water and the resulting solution sterilized by filtrationthrough a bacteriological filter prior to use. These compounds may beemployed in aqueous solutions containing other solutes for exampleenough saline or glucose to make them isotonic. They may be alsoadministered by other routes such as orally, subcutaneously andintramuscularly. For this purpose, it is useful to compound them intotablets with various tablet forming material such as'starch or toprepare elixirs or suspensions with suitable carriers.

The following examples aregiven to further illustrate the methods forsynthesizing the valuable products of this invention. However, it is tobe understood that these are given for illustrative purposes only andare not to 'be construed as limiting the invention in any way.

EXAMPLE I Pregnane-3 ,20-di0ne -21 -thiol xggssz, 5.89, 8.85 1 Thismixture of the 21-chloroand 21-p-toluenesul-.-

fonyl compounds was treated-with an equal weight of potassium iodide inacetone and refiuxedunder nitrogen for one'hour. The reaction mixturewas cooled and the insoluble salts filtered. Freshly prepared sodiumthioacetate was addedto the filtrate and the whole refluxed undernitrogen for 30 minutes. Concentration of the solvent aflforded a yellowcrystalline residuewhich was taken up in ether-benzene and washed withwater, dried over sodium sulfate and concentrated again, Trituration ofthe residue with ether gave tan prisms of pregnanc- 3,20-dione-21-th iolacetate, 142-1462.

Saponification of this material with methanolicpotassium carbonateafforded the thiol whose infrared spectrum confirmed its structure to be.pregnane-3,20;dione- ZI-thiol. 5

' EXAMPLE II PregnarIe ZZO-diUne-ZI-thi0l hemisuccinate I The mercaptopregnane derivative of Example I, 14.7 g., was dissolved in ml. of drypyridine and treated with 14 g. of succinic anhydride. The solution wasallowed to stand at room temperature overnight and then it was slowlypoured into 1.5 liters of. water. The excess pyridine was neutralizedwith 3N hydrochloric acid and the solution diluted with 2 l. of water.The product precipitated as a white cystalline solid which was cooled,washed with water and dried in vacuo at 50 C.

EXAMPLE III- Pregnane-3,20-dione-21-thiol sodium hemisuccinate Thesodium salt of the hemisuccinate ester of Example II was prepared bydissolving 1 g. of the ester in an equivalent quantity of 5% sodiumbicarbonate solution. It was necessary to warm the solution before allof the material dissolved. A clear solution then resulted which wasfiltered through a bacteriological filter to sterilize it and the clearfiltrate frozen, and dried from the'frozen state. The residue remainingwas a fluffy, white crystalline solid which was the sodium salt ofpregnane-3,20-dione- 21-thiol hemisuccinate in a suitable'condition forintravenous injection whendissolved in sterile water. A sample of thismaterial was characterized by titration.

EXAMPLE IV Allo-pregnane-ZO-one-Z]-ol-3a-thiol Allo-pregnane-ZO-one-Bfl,2l -diol 21-acetate, 5.05 g., and 4.75 g. of p-toluenesulfonyl chloridewere slurried with 25 ml. of pyridine at roomtemperature protected fromatmospheric moisture. The mixture was stored in this fashion for onedayand then the contents diluted with 150 ml. of 3 N hydrochloric acidwith stirring and cooling. The resulting precipitate of the3-p-toluenesulfonate ester was collected and washed thoroughly withwater. The mixture was dried'in vacuo over phosphorus pentoxide yielding8.3 g. of a colorless powder which was recrystallized from benzene andhexane to yield the purified 3-p-toluenesulfonate ester, M. P. 179-180C.

REE; 5.72, 5.82, 6.26, 8.11

This p-toluenesulfonate ester was then refluxed for one hour with a 10%excess of potassium thioaceta'te dissolved in thioacetic acid. Thesolvent was evaporated and the residue triturated with water to yieldallo-pregnane-20-one-2l-ol-Qa-thiol diacetate.

The diacetate was refluxed with methanolic potassium carbonate to yieldthe corresponding thiol alcohol which was recovered by pouring themixture into water, cooling the product and washing it with water. Itwas dried in vacuo over phosphorus pentoxide. This material,allo-pregnane-20-one-2l-ol-Sa-thiol, was of suitable purity for furtherconversion to the valuable ionic esters of this invention.

' 11 EXAMPLE v 'Alla-pregndne-ZO-one-ZI -l-3a-thiol 3,21 dihemisuccinateThe B-mercapto compound of Example IV, 14.7 g., was converted to thedihemisuccinate ester by treatment with 'succinic anhydride as describedin Example II. This material was further converted to the disodium saltby the procedure of Example III to yield a sterile crystalline materialsuitable for the preparation of intravenously injectable solutions ofthe anesthetic agent.

' EXAMPLE VI Pregn ar zed,ZO-dione-ZI-th'iol ZI-cklofbacetatevHregnane3,20-dionee21-thiol of Example I, 17.4 g., was dissolved inpyridine and the solution cooled in an ice bath. The cooled solution wasthen treated with 0.1 mole of chloroacetyl chloride. After the reactionhad subsided the mixture was allowed to stand at room temperatureovernight and the 2l-ehloroacetate ester isolated by pouring thepyridine solution slowly into five volumes of ice water. The precipitateproduct was collected, washed with water and dried in vacuo. Thechloroacetate ester produced by this procedure was of'suitable qualityfor conversion to various of the valuable ionic esters of this inventionby replacement of the chlorine atom.

EXAMPLE vn Pregnane-3,20-dione-2l-thi0l-21-dimeihylaminoacetatehydrochloride The chloroacetate ester of Example VI, g., was dissolvedin dimethyl formamide and treated with gaseous dimethylamine from acylinder until the gain in weight of the solution corresponded toslightly more than an equivalent quantity of dimethylamine. The productwas then precipitated by treatment of the dimethylformamide solutionwith twice its volumes of hexane. The composition of the product wasconfirmed by, determination of the ionic chlorine content by titrationwith standard silver nitrate solution.

' EXAMPLE VIII Pregrwne-3,20-di0ne-21 -thiol diethylaminoacetatehydrochloride Two grams of the chloroacetate of Example VI was dissolvedin 20 ml. of pyridine and treated with 1 m1. of diethylarnine. Themixture was kept for 16 hours in a water bath at 60 C. and the productisolated by pouring the solution into 50 ml. of cold water. The solutionwas neutralized with sodium bicarbonate and the diethylaminoacetatefreebase was recovered by extraction with methylene chloride. Evaporation ofthe solvent left an oil which was dissolved in hexane and treated withanhydrous hydrogen chloride from a cylinder. The hydrochloride saltprecipitated and was recovered, washed with fresh solvent and dried. Itsneutral equivalent determined by in an aqueous system with sodiumhydroxide and in a non-aqueous system with perchloric acid agreed withthe calculated value.

What is claimed is; g

1. .A compound having the formula CO OH: l

wherein L is chosen from the group consisting of-an alkylene radical, ahydroxyalkylene radical, the lower hydrocarbon ethers thereof, the lowerhydrocarbon acid amides thereof, an azalkylene radical, an oxalkyleneradical and a thialkylene radical wherein the heterogroups of saidradicals are selected from the group consisting of O, -S,

and -S-S and wherein said heterogroups are attached to saturated carbonatoms and said L group 'contains up to about six atoms in its principalchain; M+ is a cation selected from the group consisting of sodium,potassium and NR+, each R represents a member of the group consisting ofa hydrogen atom, and a lower hydrocarbon group containing up to aboutsix carbon atoms; Z is a pharmacologically acceptable anion; (b)hydroxyl, and the lower hydrocarbon carboxylic acid esters thereofcontaining up to about eight carbon atoms in the added unit; (c) keto;(d) mercapto, lower hydrocarbon sulfides, and hydrocarbon carboxylicacid thioesters thereof having up to about eight carbon atoms in theadded unit; E is selected from the group consisting of (a) ionic estergroups as defined above; (b) hydroxyl, and lower hydrocarbon carboxylicacid esters thereof containing up to about eight carbon atoms in theadded unit; (0) hydrogen; (d) mercapto, lower hydrocarbon sulfides, andlower hydrocarbon carboxylic acid esters thereof containing up to abouteight carbon atoms in the added unit; and with at least one of D and Ebeing an ionic ester group as defined above and one of D and Econtaining nuclearly attached sulfur.

2. A pharmaceutical composition which comprises a compound as claimed inclaim 1 together with a pharmaceutically acceptable carrier.

3. An anesthetic agent comprising a sterile aqueous solution of acompound as claimed in claim 1.

4. Allo-pregnane-ZO-one-Z1-ol-3ec-thiol.

5. Pregnane-3,20-dione-2l-thiol sodium hemisuccinate.

6. Allo-pregnane-3,20-dione-21-thiol sodium hemisuccinate.

7. Pregnane-3,20-dione 21 thiol diethylaminoacetate hydrochloride.

References Cited in the file of this patent UNITED STATES PATENTS2,304,836 Marker Dec. 15, 1942 2,429,171 Ruzicka Oct. 14, 1947 2,582,918Bernstein et a1. Jan. 15, 1952 2,623,054 Levin et al. Dec. 23, 19522,693,476 Cummings et al Nov. 2, 1954 2,693,484 Cummings et a1. Nov. 2,1954 2,697,108 Rosenkranz et al Dec. 14, 1954 2,708,651 Laubach May 17,1955 2,744,109 Ralls May 1, 1956 2,814,632 Nussbaum Nov. 26, 1957FOREIGN PATENTS 476,023 Canada Aug. 14, 1951 476,135 Canada Aug. 14,1951 Great Britain Oct. 31, 1951 OTHER REFERENCES Djerassi et al.: J.Am. Chem. Soc., vol. 75: 3702 (1953).

1. A COMPOUND HAVING THE FORMULA
 3. AN ANESTHETIC AGENT CONPRISING ASTERILE AQUEOUS SOLUTION OF A COMPOUND AS CLAIMED IN CLAIM 1.